Altered cells deliver Parkinson’s therapy to brain

Tuesday December 27, 2005

Dec 27, 2005 (Reuters Health) - Genetically modified nerve ’progenitor’ cells can be used as mini-pumps to deliver nerve growth factor to the brain, a new study in animals shows.

The results suggest such an approach could be used to treat Parkinson’s disease and other brain diseases in humans, Dr. Clive D. Svendsen of the University of Wisconsin-Madison and colleagues report.

A nerve growth factor called "glial cell line-derived neurotrophic factor" (abbreviated to GDNF) has been shown to protect dopamine-producing neurons, which are lost in Parkinson’s disease, Svendsen and his team note in the research journal Gene Therapy.

In fact, it’s safe to infuse GDNF into brain regions of patients with Parkinson’s disease, according to some studies, and it seems effective. However, delivering the drug in this fashion is complex and only reaches a single point in the brain.

In the current study, using rats with symptoms akin to Parkinson’s disease, the researchers investigated the effect of human neural progenitor cells engineered to produce GDNF.

The rats were transplanted with the modified cells, and after two weeks these were seen to have migrated to affected areas and to be secreting enough GDNF to extend the survival of dopamine neurons and promote outgrowth of nerve fibers.

By five weeks post-transplant, the animals showed a "strong trend toward functional improvement," and at eight weeks the cells were still releasing the growth factor.

Tests in elderly monkeys showed the cells survived and continued to release GDNF for three months after transplant. None of the animals in the studies developed brain tumors.

Svendsen and his colleagues conclude that their results "show that combining human progenitor cell therapy with ... gene therapy is a powerful approach to the future treatment of Parkinson’s disease and other neurological conditions."